Question about 1996 Mitsubishi Galant

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Idle Air Control/Check Engine Light

My car has slowly been consuming more gas. Recently the check engine light came on. I took it to the street mechanic close by and he tested it on the dash. Gave code P0505. He doesn't know what the hell the Idle Air Control System is, and he wanted me to replace the whole electronics for $500 even though it was getting power. I read up and I don't seem to have the symptoms with my car when it's in idle that most people do. It idles fine. Only uses a LOT of gas now. Could there be another problem with it? 1996 Mitsubishi Galant S

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  • Dan Todd May 11, 2010

    An idle air control valve system will run about $250 for your engine.

    But if you aren't experiencing idle symptoms, erratic, not fast when it is cold, then the code might not have been correct.

    In my opinion the wrong way to diagnose a problem is to start throwing parts at it until it's fixed. I assume by now he cleared the code out and perhaps you are not getting the check engine light. But if you do, I would take it to a dealer and have them check it out.

    The analysis will cost you, but then you might go somewhere else or buy the parts and do it yourself if mechanically inclined.

    If you run across another street mechanic who "doesn't know what the hell an air cobtrol system is", run, don't walk away from there.



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There are a lot of sensors that help the computer adjust the idle. Any one of them could be at fault. You'll have to take your car to get diagnosed. Mechanics are good at guessing and replacing things at random. Have it diagnosed and find out what needs to be changed for sure. What you can do is check for vacuum leaks. Try to remember if any work was done and where check around the area for loose, cracked or disconnected vacuum hoses. Also check for striped, disconnect cables or wires etc. Any air coming in after the mass air flow sensor will throw the computer off. Yea don't replace anything at all without knowing its the cause. Give it a tune-up replace the air filter, ignition components, fuel filter and pressure regulator also the engine oil and filter. This is the cheapest way and it could get it fixed! Plus you got to do it any ways. After the tune-up restart the computer, disconnect the negative or ground cable from the battery. Wait five minutes then reconnect, this is an important step. The computer will now set for the new air filter, ignition etc. and adjust the idle accordingly. If the check engine comes back on then you have a problem that goes beyond this. Then you'll know you have to have it diagnosed for sure.

Posted on May 14, 2009

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